如何制作“数据透视表"在 Ruby on Rails 上? [英] How to make a "pivot table" on Ruby on Rails?

问题描述

首先，我想说我对 Ruby 和 Rails 完全陌生，我刚刚开始学习，所以如果我的问题看起来有点不清楚或过于宽泛，我深表歉意.

First, I'd like to mention I'm COMPLETELY new to Ruby and Rails, I'm on my very first days of learning, so I apologize if I seem a bit unclear or too broad with my questions.

我正在尝试做一些简单的事情(我认为?)，即旋转表格.

I'm trying to do something simple (I think?), which is to pivot a table.

我有一张看起来像这样的表格:

I have a table that looks like this:

----------------------------------
| Name     | Product ID | Amount |
|----------|----------------------
| Robert   |     P1     |   2    |
| Michael  |     P2     |   1    |
| Leonard  |     P2     |   1    |
| Robert   |     P2     |   4    |
| Robert   |     P3     |   2    |
| Michael  |     P3     |   1    |
----------------------------------

...我想把它变成这样:

... and I'd like to to turn it into something like this:

---------------------------
| Name     | P1 | P2 | P3 |
---------------------------
| Robert   | 2  | 4  | 2  |
| Michael  | -  | 1  | 1  |
| Leonard  | -  | 1  | -  |
---------------------------

我不太确定如何实现这一目标.我环顾四周，没有发现任何针对我的问题的内容.

I'm not too sure how to achieve that. I've looked around and haven't found anything specific to my question.

我找到了一个名为 pivot_table 的 gem，可以在这里找到:https://github.com/edjames/pivot_table 但我不知道如何确切地使用它.里面有一个小指南，但我不知道把代码放在哪里.

I found a gem called pivot_table, which can be found here: https://github.com/edjames/pivot_table but I have no clue how to exactly use it. It has a small guide in it, but I don't know where to place the code.

非常感谢任何帮助.

谢谢.

推荐答案

看着你的表和你正在寻找的结果，我会这样做(我假设它是一个订单表?)

Looking at your table and the results you're looking for, I would do it like this ( I assume it's an orders table ?)

result = []
Order.all.group_by(&:name).each do |name, orders|
  record = {}
  record["name"] = name
  orders.each do |order|
    record[order.product_id] = order.amount
  end
  result.append(record)
end 

我希望这会给你一个好的起点！

I hope this will give you a good starting point !

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